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    <title>Document</title>
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    <script>
      /* 
      1. pow(2, 4)=16 return 2 * pow(2, 3); 
      2. pow(2, 3)=8 return 2 * pow(2, 2); 
      3. pow(2, 2)=4 return 2 * pow(2, 1); 
      3. pow(2, 1)=2 return 2;
      */
      function pow(x, n) {
        if (n === 1) return x;
        return x * pow(x, n - 1);
      }
      console.log(pow(2, 4));
    </script>
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